THE QUESTION OF WATER- ABSORPTION BY FOLIAGE LEAVES. 213 



THE QUESTION OF WATEK-ABSORPTION BY FOLIAGE 



LEAVES. 



J. B. DAXDEXO^ AGRICULTURAL COLLEGE. 



As early as 1679 Marriotte gives an account of some investigations 

 and concludes that water may be readily absorbed by leaves. Then Hales, 

 1725, Bonnet, 17.54, Senebier, 1800, Dutrocliet, 1837, and a few others 

 publish results similar to those of INfarriotte. Views opposed to these 

 were published by Treviranus, 1835, Duchartre, 18G1 ; and especially by 

 manv of the more recent text-books on Plant Phvsiologv. such as Pfeffer, 

 Detmer and Vines. Special papers by Garreau, 1849, Cailletet, 1872, 

 Boehm, 1877. Mer. 1878, Bonssingault, 1878, and Henslow, 1880, assert 

 in substance as did ^larriotte and Hales. The views as expressed by 

 text-books are in general opposed to that of water absorption. 



The experiments to inquire into the truth of the matter were in brief 

 as follows : 



1. Semi- wilted leaves were weighed, then immersed in water for short 

 periods (from one to twenty-fours hours) then the weight and the visible 

 turgidity taken into account. , 



2. Repetition of Hale's experiment. 



3. Using a manometer where water is applied to one side of a leaf 

 at a time. 



These factors were also taken into consideration : 



1. Distilled water applied to the surfaces of leaves for a short time 

 usually becomes alkaline and extracts a saline matter from the leaf. 



2. The anatomic structures of the leaf. 



3. The positive proof that dilute solutions are absorbed by leaves. 



SUMMARY OF THE MORE IMPORTANT FACTS. 



1. Leaves may absorb water through the surface whether stomata 

 be present or not. 



2. In connection with this there general]}' occurs a loss of saline sub- 

 stance, consequently rain water may aid in relieving the leaves of sur- 

 plus salts, and conse(iuently may help in excretion. 



3. In the drenching of lettuce leaves, it is quite probable that the 

 change in flavor may be due to the loss of substance extracted by Ihe 

 water. 



4. The strongest experimental evidence in su])port of absorption de- 

 velop from the fact fa) that solutions are readily absorbed, (b) that 

 water extracts substances, (c) that an immersed leaf or branch may 

 contribute plainly toward the turgidity of a neighboring branch or leaf. 



